In an “ad hoc” wireless network, all nodes of the network are equipped with wireless communications transceivers. Some of the nodes, commonly known as routers or switches (hereinafter referred to as “routers”), are capable of directing traffic (messages) on the network, e.g., network routing functions. Other of the nodes, commonly known as “endpoints,” are sources and/or destinations of data traffic.
Each node in an “ad hoc” wireless network typically executes a set of algorithms and conforms to a set of networking protocols which enable the nodes to locate other nodes. The protocols also enable the nodes to determine paths through the network for sending and receiving data traffic from source to destination. Additionally, the protocols enable the nodes to detect changes and/or repair ruptures in the network, which may occur when nodes enter, move, fail or leave the network, when battery-power changes, when communication path characteristics change over time, and the like.
Certain types of “ad hoc” wireless networks employ beacons as a means by which nodes can discover or convey information to other nearby nodes. A beacon is a broadcast transmission that can be received by some or all of the nodes within transmission range—as opposed to a point-to-point transmission to a particular node. In some network schemes, all of the nodes in the network can broadcast beacons; in other networks, only a subset of the nodes can broadcast beacons.
Typically beacons contain various fields of information, such as an identification of the node that is transmitting the beacon, forwarding error correction information (to ensure correct receipt of the beacon), and other fields depending on the type of wireless networking protocols employed in the network.
Beacons have a substantial drawback when used in military networks. In such tactical situations, an adversary or enemy may try to monitor and/or disrupt network communications. Beacon messages are particularly easy for an enemy to notice, because they are generally sent at more or less regular intervals, at high power, and often on a well-known wireless channel. The enemy can thus readily identify all of the nodes in the network simply by monitoring their beacon transmissions. In addition, the enemy can jam and/or disrupt the network by delivering jamming energy at those times and places where nodes are expected to beacon.